The reality is, when you get a little bit of seniority with FedEx, you'll probably be able to hold some deadhead trips. Then if you can't jumpseat on FedEx (which we like to do, because it's practically a guaranteed ride into work, rarely bumped), you can have FedEx pay for a commercial ticket to work, and you collect the airmiles. Dallas is close, seems like an easy commute into Memphis. Many of our trips start/end elsewhere with a deadhead, so soon enough you might not have to get into Memphis anyways. I rarely jumpseat, avoid that whenever possible. And I hate jumpseating on anyone but FedEx, I like the guarantee of a ride. Commuting while working at FedEx is an entirely different deal than other carriers. Living in Dallas, you'll probably end up being AAdvantage Platinum on American every year, anyways.
However, the first thing I'd worry about is getting the job. The commute will be fine. Just get the job.